Back-draft valve

ABSTRACT

A BACK-DRAFT VALVE FOR USE WITH A BLAST FURNACE INCLUDES A WATER-COOLED VALVE SEAT PANEL THAT IS REMOVABLE AND REPLACEABLE AND THAT HAS A LOCKING MECHANISM TO SECURE THE VALVE SEAT IN POSITION. ALSO INCLUDED IS A FRUSTOCONICAL REFRACTORY LINING ON THE FLUID ENTRANCE PASSAGEWAY AND A CYLINDRICAL REFRACTORY LINING ON THE FLUID EXIT PASSAGEWAY OF THE VALVE HOUSING.

NW. 2, 19% J. A. VIETORISZ 3,616,812

BACK-DRAFT VALVE Filed July 23, 1969 2 Sheets-Sheet 1 MGM I NVENTOR.

J05EPH A. V/ETOR/SZ cS MMM V/QUJJVL NOW, 2, 1971 vlETORlSZ 3,616,812

BACK-DRAFT VALVE Filed July 23, 1969 2 Sheets-Shoot 2 I NVENTOR.

JOSEPH A. V/ETOR/SZ mgzwm United States Patent whee 3,616,812 PatentedNov. 2., 1971 3,616,812 BACK-DRAFT VALVE Joseph A. Vietorisz,Pittsburgh, Pa., assignor to Koppers Company, Inc. Filed July 23, 1969,Ser. No. 844,136 Int. Cl. F16k 49/00 U.S. Cl. 137340 2 Claims ABSTRACTOF THE DISCLOSURE A back-draft valve for use with a blast furnaceincludes a water-cooled valve seat panel that is removable andreplaceable and that has a locking mechanism to secure the valve seat inposition. Also included is a frustoconical refractory lining on thefluid entrance passageway and a cylindrical refractory lining on thefluid exit passageway of the valve housing.

BACKGROUND OF THE INVENTION Whenever it is necessary to make repairs toor to maintain a blast furnace, such repairs being, for example, toremove and replace a worn tuyere or a blow pipe, it is necessary todivert the gases from the hearth zone of the blast furnace into a stackso that such repairs and maintenance may be carried out by workmen whowill not be exposed to the high temperatures of the gases flowing fromthe furnace hearth.

Before undertaking such repair or maintenance work, it is necessary tomake sure that all of the valves in the hot blast main leading from thehot blast stoves to the bustle pipe are closed, and that a back-draftvalve in a horizontal conduit that branches off from the hot blast mainor bustle pipe and that leads to the stack, is opened. Then, the gasesin the hot blast main and in the hearth zone flow through the back-draftvalve and into the stack.

The open back-draft valve, therefore, allows any flammable gases in thehearth zone to flow toward the stack.

These flammable gases mix with hot blast air and com bustion of thegases occurs for a short period of time in the horizontal conduit.Hence, the back-draft valve may be exposed for a short period of time tovery hot flame temperatures produced by the burning gases.

The valve of the invention is capable of withstanding such very highflame temperature, and yet is readily actuated to close and open thehorizontal conduit to allow the hot blast air and flammable gases toescape into the stack.

SUMMARY OF THE INVENTION A back-draft valve for use with a blast furnaceincludes a water-cooled valve seat panel that is removable andreplaceable and that is suspended within the housing. Means cooperatingwith the housing and with the valve seat panel urge it into fixedcooperative relation with the housing. The fluid entrance passageway ofthe housing is covered internally with a frusto-conical refractoryshaped lining and the fluid exit passageway in the housing is coveredinternally with a cylindrical shaped refractory lining.

BRIEF DESCRIPTION OF THE DRAWING The drawing illustrates one embodimentof the invention in which:

FIG. 1 is an elevational view, partly in section, of a back-draft valvein accordance with the invention;

FIG. 2 is a view along line IIII of FIG. 1;

FIG. 3 is a view along line IIIIII of FIG. 1; and

FIG. 4 is a view along line VV of FIG. 3.

DETAILED DESCRIPTION The valve 11 of FIG. 1 is a gate valve having ahousing 13 and a valve bonnet 15 bolted to the housing 13. Internally,the valve 11 includes a valve disc 17 that may be similar to the valvedisc disclosed in application Ser. No. 594,058, filed Nov. 14, 1966 nowPat. 3,511,262. Such valve disc is water-cooled and cooperates with afluid cooled seat valve 33 that is disposed in the housing 13 on thedownstream side of the valve disc 17. Hot gases flow through the valve11 along a flow axis indicated by an arrow, A, of FIG. 2.

The valve housing 13, in the region of the valve opening is constructedas shown in FIG. 2. That is to say, a frusto-conical steel supportingring 19 is secured both to a fluid entrance flange 21 on the housing 13,and to a vertical wall 23 of the fluid cooled housing 13. A triangularshaped space 25 formed by the frusto-conical supporting ring 19, thehousing 13, and the flange 21 is used to convey a suitable fluid forcooling the adjacent members.

The inner surface of the frusto-conical ring member 19 is covered with alayer 27 of refractory material, and the inner surface 29 of therefractory materials is frusto-conical in shape, for a purpose that willbe explained hereinafter.

The opposite side of the valve housing 13, is also provided with afrusto-conical steel supporting ring 31 that is disposed so as to form asupport for a water-cooled valve seat panel 33. The supporting ring 31is also covered with a refractory lining 35, but such refractory lininghas a cylindrical internal surface 37. A triangular shaped cooling waterpassage 39 is also provided in the valve housing around the supportingring 31.

In order for the back-draft valve 11 of the invention to be fullyeffective, it is essential that the valve seat panel 33 be locked in acentral position in the housing 13. Positioning of the valve seat panel33 in a proper central axial position is effected by means of amechanism 40 comprising a pair of wedges 41 suitably applied to thevalve seat panel 33 that cooperate with the side brackets 43 mounted tothe valve seat panel, and with eccentric rollers 45 mounted on shaft 47.

It will be noted that in FIG. 1 only the valve seat locking mechanism 40on the right hand side of the valve 11 has been shown, but it should beunderstood that the valve seat positioning mechanism 40 on the left handside of the valve 11 is similar, but to an opposite hand.

A pair of stoppers 49 are welded, or otherwise suitably fixed, to ahousing portion 51 that is connected to the frusto-conical supportingrings 19, 31.

The top edge 53 of the stoppers 49, and the bottom edge 55 of the sidebrackets 43 are so located in relation to each other that, when the sidebrackets 43 coact with the stoppers 49, the horizontal center line ofthe valve disc 17, in the closed position, will be in the horizontalplane of the water-cooled valve seat 33. Also, the side stoppers 49coact with the wedges 41 and position the valve disc 17 centrally in thevalve housing 13 so that the vertical center line axis of the valvehousing 13 will coincide with the vertical center line of the seatpanel.

The eccentric roller 45 is mounted to the shaft 47 that is journaled inthe housing 13 about as shown in FIG. 3, and is rotatable by means ofany suitable tool applied to a protruding shaped end 57 of the shaft 47.On the protruding shaft end 57, there is a lock nut 59 that secures andholds the roller 45 in any desired position. When the roller shaft 47 isrotated, the eccentric roller 45 coacts with a curved surface 61 of theside brackets 43 to urge the valve seat panel 33 into fixed cooperativerelation with the frusto-conical supporting ring 31. The surface 61 maybe curved as shown, or it may be straight and a portion of a wedge, ifpreferred.

The interaction of the eccentric roller 45 and the curved surface 61 ofthe side brackets 43 prevents any upward movement of the valve seatpanels 33 when the valve disc 17 is raised to its open position.

The valve seat panel 33 is cooled internally by water flowing thereintothrough an inlet conduit 63, and flowing therefrom through an outletconduit 65. The conduits 63,

65 pass through conventional glands (not shown) in the valve housing 13.

Thus, the valve seat panel 33, locked in at two sides of its horizontalcenter line by the mechanisms 40, can freely expand horizontally when itis exposed to heat; there being predetermined clearances between thewedges 41 and the stoppers 49. The valve seat panel 33 hangs freelydownward below the stoppers 49. Only the weight of the valve seat paneland the friction in the glands, which is easily overcome, resist thethermal expansion forces acting on the heated valve seat panel 33. Thevalve seat panel is fork-shaped, as shown in FIG. 1 at 66, and is cooledinternally. Therefore, the thermal movements will be small and thethermal forces will be well within tolerable limits.

The protruding shaped end 57 of the shaft 47 is covered with a removablecap 67 having a cylindrical part 69 that may be fitted onto the housingin which the shaft 47 is journaled.

As mentioned previously, the fluid entrance passageway in the valvehousing is covered internally with a frustoconically shaped refractorylining 27. It may be noticed from FIG. 2, the inner frusto-conicalsurface 29 converges in the direction of the fluid flow, A, so that hotgases entering the valve 11, are directed slightly toward the centerline flow axis. Thus, the hot gases are directed away from the sealingface of the fluid cooled valve seat panel.

Although, the locking and centering positioning mechanism 40, as well asthe frusto-conical shaped lining are described herein with reference toa back-draft valve, it is understood that the present invention is notlimited to only a back-draft valve, and it may be applicable to anyvalve of the gate type.

From the foregoing description of an embodiment of the invention, thoseskilled in the art will recognize several significant features andadvantages, among which are:

That the valve seat panel is effectively centered and securely locked inthe valve housing in a simple manner;

That the locking device is readily and easily serviceable from outsideof the valve housing;

That the valve seat panel is not subjected to excessive stresses due tothermal expansion; and

That the internal refractory lining covering the fluid inlet flowpassageway is frusto-conical to direct the hot gases flowing through thevalve away from the sealing face of the valve seat panel.

What is claimed is:

1. In a gate valve having a housing with entrance and exit passagewaysand a valve disc moveable therein to regulate the flow of fluid along anaxis through said gate valve, the improvement comprising:

(a) a fluid cooled valve seat panel disposed in said housing;

(b) a pair of spaced apart stoppers mounted to said housing;

(c) a pair of spaced apart brackets that are mounted to said valve seatpanel and that are cooperative with respective stoppers;

(d) a pair of diametrically opposed wedges mounted to said valve seatpanel that cooperate with said stoppers to center said valve seat panelin said hous- 111g;

(e) a pair of spaced apart side brackets that are mounted to said valveseat panel, and that have one surface that is cooperative with (f) aneccentrically mounted roller fixed to a shaft journaled in said housingwith;

(g) means for rotating said shaft and roller to urge said valve seatpanel towards and into cooperative fixed relation with said housing;

(h) a refractory lining on the internal surface of the entrancepassageway of said valve, said lining having a frusto-conical internalsurface converging in the direction of fluid flow through said valve;and

(i) refractory lining on the internal surface of the exit passageway ofsaid valve, said lining having an internal cylindrical surface that iscoaxial with the fluid flow axis through said valve.

2. In a gate valve having a housing with "both an entrance and an exitpassageway and having a valve disc movable therein to regulate the flowof fluid along an axis through said valve, the improvement comprising:

(a) a fluid-cooled valve seat panel disposed in said housing;

(b) means on said seat panel coacting with fixed means on said housingfor supporting said seat panel in a central axially aligned position insaid housing;

(0) a pair of spaced apart side brackets mounted onto said valve seatpanel with one surface of each bracket cooperating with (d) aneccentrically mounted roller fixed to a shaft journaled in said housing;

(e) means for rotating said shaft and roller to urge said valve seatpanel towards and into cooperation with said housing; and

(f) refractory lining disposed over the interior surfaces of both theentrance and the exit passageways of said valve housing.

References Cited UNITED STATES PATENTS 3,040,773 6/ 1962 McInerney137-340 X 3,068,888 12/1962 Mohr, Jr. 251-158 X 3,126,941 3/1964 Mohr etal. 137340 X 3,171,429 3/1965 Sturrner et al 251-159 X 3,207,174 9/1965Berczynski 137340 X 3,266,517 8/1966 Carr 137340 3,430,689 3/1969 Pantkeet a1 137340 X SAMUEL SCOTT, Primary Examiner

